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rustc: Group the variable binding machinery into a separate data structure during unification

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This commit is contained in:
Patrick Walton 2011-05-18 11:53:26 -07:00
parent a795d0e5b2
commit 37d5dd9471
1 changed files with 33 additions and 29 deletions
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62
src/comp/middle/ty.rs
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@ -1865,9 +1865,18 @@ mod unify {
ures_err(type_err, t, t);
}
type ctxt = rec(ufind::ufind sets,
hashmap[int,uint] var_ids,
mutable vec[mutable vec[t]] types,
type var_bindings = rec(ufind::ufind sets,
hashmap[int,uint] var_ids,
mutable vec[mutable vec[t]] types);
fn mk_var_bindings() -> var_bindings {
let vec[mutable vec[t]] types = [mutable];
ret rec(sets=ufind::make(),
var_ids=common::new_int_hash[uint](),
mutable types=types);
}
type ctxt = rec(var_bindings var_bindings,
unify_handler handler,
ty_ctxt tcx);
@ -2070,12 +2079,12 @@ fn unify_obj(&@ctxt cx,
fn get_or_create_set(&@ctxt cx, int id) -> uint {
auto set_num;
alt (cx.var_ids.find(id)) {
case (none[uint]) {
set_num = ufind::make_set(cx.sets);
cx.var_ids.insert(id, set_num);
}
case (some[uint](?n)) { set_num = n; }
alt (cx.var_bindings.var_ids.find(id)) {
case (none[uint]) {
set_num = ufind::make_set(cx.var_bindings.sets);
cx.var_bindings.var_ids.insert(id, set_num);
}
case (some[uint](?n)) { set_num = n; }
}
ret set_num;
}
@ -2098,17 +2107,18 @@ fn unify_step(&@ctxt cx, &t expected, &t actual) -> result {
alt (struct(cx.tcx, expected)) {
case (ty::ty_var(?expected_id)) {
auto expected_n = get_or_create_set(cx, expected_id);
ufind::union(cx.sets, expected_n, actual_n);
ufind::union(cx.var_bindings.sets, expected_n,
actual_n);
}
case (_) {
// Just bind the type variable to the expected type.
auto vlen = vec::len[vec[t]](cx.types);
auto vlen = vec::len[vec[t]](cx.var_bindings.types);
if (actual_n < vlen) {
cx.types.(actual_n) += [expected];
cx.var_bindings.types.(actual_n) += [expected];
} else {
assert (actual_n == vlen);
cx.types += [mutable [expected]];
cx.var_bindings.types += [mutable [expected]];
}
}
}
@ -2472,12 +2482,12 @@ fn unify_step(&@ctxt cx, &t expected, &t actual) -> result {
case (ty::ty_var(?expected_id)) {
// Add a binding.
auto expected_n = get_or_create_set(cx, expected_id);
auto vlen = vec::len[vec[t]](cx.types);
auto vlen = vec::len[vec[t]](cx.var_bindings.types);
if (expected_n < vlen) {
cx.types.(expected_n) += [actual];
cx.var_bindings.types.(expected_n) += [actual];
} else {
assert (expected_n == vlen);
cx.types += [mutable [actual]];
cx.var_bindings.types += [mutable [actual]];
}
ret ures_ok(expected);
}
@ -2517,9 +2527,9 @@ fn substitute(&@ctxt cx, &vec[t] set_types, &t typ) -> t {
fn substituter(@ctxt cx, vec[t] types, t typ) -> t {
alt (struct(cx.tcx, typ)) {
case (ty_var(?id)) {
alt (cx.var_ids.find(id)) {
alt (cx.var_bindings.var_ids.find(id)) {
case (some[uint](?n)) {
auto root = ufind::find(cx.sets, n);
auto root = ufind::find(cx.var_bindings.sets, n);
ret types.(root);
}
case (none[uint]) { ret typ; }
@ -2538,15 +2548,15 @@ fn unify_sets(&@ctxt cx) -> vec[t] {
let vec[mutable vec[t]] set_types = [mutable throwaway];
vec::pop[vec[t]](set_types); // FIXME: botch
for (ufind::node node in cx.sets.nodes) {
for (ufind::node node in cx.var_bindings.sets.nodes) {
let vec[t] v = [];
set_types += [mutable v];
}
auto i = 0u;
while (i < vec::len[vec[t]](set_types)) {
auto root = ufind::find(cx.sets, i);
set_types.(root) += cx.types.(i);
auto root = ufind::find(cx.var_bindings.sets, i);
set_types.(root) += cx.var_bindings.types.(i);
i += 1u;
}
@ -2567,13 +2577,7 @@ fn unify(&t expected,
&t actual,
&unify_handler handler,
&ty_ctxt tcx) -> result {
let vec[t] throwaway = [];
let vec[mutable vec[t]] types = [mutable throwaway];
vec::pop[vec[t]](types); // FIXME: botch
auto cx = @rec(sets=ufind::make(),
var_ids=common::new_int_hash[uint](),
mutable types=types,
auto cx = @rec(var_bindings=mk_var_bindings(),
handler=handler,
tcx=tcx);
@ -2582,7 +2586,7 @@ fn unify(&t expected,
case (ures_ok(?typ)) {
// Fast path: if there are no local variables, don't perform
// substitutions.
if (vec::len(cx.sets.nodes) == 0u) {
if (vec::len(cx.var_bindings.sets.nodes) == 0u) {
ret ures_ok(typ);
}